Massive volcanic eruptions of the Deccan Traps caused dinosaur extinction, not the asteroid.
While the Deccan Traps volcanism was contemporaneous and contributed to K-Pg extinction through climate disruption and atmospheric effects, it was not the sole cause. The Chicxulub asteroid impact provided the catastrophic trigger that finished an already-stressed ecosystem. Isotopic and paleomagnetic evidence places volcanism before and after the impact, but the impact's sudden climatic perturbation caused the extinction event. Models show volcanism alone would have caused disruption but not total extinction; the asteroid provided the final blow. Scientific consensus supports a dual-causation model.